"Bladder" redirects here. For other uses, see bladder (disambiguation).
| Urinary bladder |
1. Human urinary system: 2. Kidney, 3. Renal pelvis, 4. Ureter, 5. Urinary bladder, 6. Urethra. (Left side with frontal section)
7. Adrenal gland
Vessels: 8. Renal artery and vein, 9. Inferior vena cava, 10. Abdominal aorta, 11. Common iliac artery and vein
With transparency: 12. Liver, 13. Large intestine, 14. Pelvis |
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Female bladder (visible due to lack of prostate), showing transitional epithelium as well as part of the wall in a histological cut-out.
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| Latin |
vesica urinaria |
| Gray's |
[1] |
| System |
Urinary system |
| Artery |
Superior vesical artery
Inferior vesical artery
Umbilical artery
Vaginal artery |
| Vein |
Vesical venous plexus |
| Nerve |
Vesical nervous plexus |
| Precursor |
urogenital sinus |
| MeSH |
Bladder |
Dorlands
/Elsevier |
Urinary bladder |
The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow[1] muscular, and distensible (or elastic) organ, the bladder sits on the pelvic floor. Urine enters the bladder via the ureters and exits via the urethra. It's almost impossible to give an exact measurement for the volume of the human bladder, but different sources mention 500 mL (~17 oz) to 1000 mL (~34 oz).[2]
Contents
- 1 Structure
- 1.1 Detrusor muscle
- 1.2 Fundus
- 1.3 Innervation
- 1.4 Histology
- 1.5 Development
- 1.6 In other animals
- 2 Function
- 3 Clinical significance
- 4 Additional images
- 5 See also
- 6 References
- 7 External links
Structure
Detrusor muscle
The detrusor muscle is a layer of the urinary bladder wall made of smooth muscle fibers arranged in spiral, longitudinal, and circular bundles. When the bladder is stretched, this signals the parasympathetic nervous system to contract the detrusor muscle. This encourages the bladder to expel urine through the urethra.
Fundus
The fundus of the bladder is the base of the bladder, formed by the posterior wall. It is lymphatically drained by the external iliac lymph nodes. The peritoneum lies superior to the fundus.
Innervation
The bladder receives motor innervation from both sympathetic fibers, most of which arise from the hypogastric plexuses and nerves, and parasympathetic fibers, which come from the pelvic splanchnic nerves and the inferior hypogastric plexus.[3]
Sensation from the bladder is transmitted to the central nervous system (CNS) via general visceral afferent fibers (GVA). GVA fibers on the superior surface follow the course of the sympathetic efferent nerves back to the CNS, while GVA fibers on the inferior portion of the bladder follow the course of the parasympathetic efferents.[3]
For the urine to exit the bladder, both the autonomically controlled internal sphincter and the voluntarily controlled external sphincter must be opened. Problems with these muscles can lead to incontinence.[4]
Histology
Since the urinary bladder has a transitional epithelium, it does not produce mucus.[5]
Development
The human urinary bladder is derived in embryo from the urogenital sinus and, it is initially continuous with the allantois. In males, the base of the bladder lies between the rectum and the pubic symphysis. It is superior to the prostate, and separated from the rectum by the rectovesical excavation. In females, the bladder sits inferior to the uterus and anterior to the vagina; thus, its maximum capacity is lower than in males. It is separated from the uterus by the vesicouterine excavation. In infants and young children, the urinary bladder is in the abdomen even when empty.[6]
In other animals
Bladders occur throughout much of the animal kingdom, but are very diverse in form[further explanation needed] and in some cases are not homologous with the urinary bladder in humans.[citation needed]
Function
Main article: Urination
The urinary bladder usually holds 300-350 ml of urine. As urine accumulates, the rugae flatten and the wall of the bladder thins as it stretches, allowing the bladder to store larger amounts of urine without a significant rise in internal pressure.[7]
Frequent urination can be due to excessive urine production, small bladder capacity, irritability or incomplete emptying. Males with an enlarged prostate urinate more frequently. One definition of overactive bladder is when a person urinates more than eight times per day,[8] though there can be other causes of urination frequency.[citation needed] Though both urinary frequency and volumes have been shown to have a circadian rhythm, meaning day and night cycles,[9] it is not entirely clear how these are disturbed in the overactive bladder.
Clinical significance
Disorders
Main article: Urinary bladder disease
A diverticulum of the bladder
Disorders of or related to the bladder include:
- Bladder cancer
- Bladder exstrophy
- Bladder infection
- Bladder spasm
- Bladder sphincter dyssynergia, a condition in which the sufferer cannot coordinate relaxation of the urethra sphincter with the contraction of the bladder muscles
- Bladder stones
- Cystitis
- Hematuria, or presence of blood in the urine, is a reason to seek medical attention without delay, as it is a symptom of bladder cancer as well as bladder and kidney stones
- Interstitial Cystitis
- Overactive bladder, a condition that affects a large number of people
- Paruresis
- Urinary incontinence
- Urinary retention
Additional images
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Dissection of side wall of pelvis showing sacral and pudendal plexuses. (Bladder visible at lower left.)
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Median sagittal section of female pelvis.
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The peritoneum of the male pelvis.
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Median sagitta section of male pelvis.
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Vertical section of bladder, penis, and urethra.
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Vertical section of bladder wall.
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Fundus of the bladder with the vesiculæ seminales.
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Female pelvis and its contents, seen from above and in front.
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The bladder can be seen highlighted in yellow in the illustration.
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Layers of the urinary bladder wall and cross section of the detrusor muscle.
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Urinary bladder (black butterfly-like shape) and hyperplastic prostate (BPH) visualized by Medical ultrasonography technique.
See also
- Artificial urinary bladder
- Bladder augmentation
- Neurogenic bladder
- Ureterocele
- Urodynamics
- Uvula of urinary bladder
- Vesicouretic reflux
References
- ^ Howard A. Werman, Keith J. Karren.[full citation needed]
- ^ Volume of a Human Bladder
- ^ a b Moore, Keith; Anne Agur (2007). Essential Clinical Anatomy, Third Edition. Lippincott Williams & Wilkins. pp. 227–228. ISBN 0-7817-6274-X.
- ^ "Urinary Incontinence - Causes". NHS. Retrieved 2013-08-21.
- ^ Chin T, Liu , Tsai H, Wei C (September 2007). "Vaginal reconstruction using urinary bladder flap in a patient with cloacal malformation". Journal of Pediatric Surgery 42 (9): 1612–5. doi:10.1016/j.jpedsurg.2007.04.040. PMID 17848259.
- ^ Moore, Keith L.; Dalley, Arthur F (2006). Clinically Oriented Anatomy (5th ed.). Lippincott Williams & Wilkins.
- ^ Marieb, Mallatt. "23". Human Anatomy (5th ed.). Pearson International. p. 700.
- ^ "Overactive Bladder". Cornell Medical College. Retrieved 2013-08-21.
- ^ Negoro, Hiromitsu (2012). Involvement of urinary bladder Connexin43 and the circadian clock in coordination of diurnal micturition rhythm. doi:10.1038/ncomms1812.
External links
- Histology at KUMC epithel-epith09 "Urinary Bladder"
- Organology at UC Davis Urinary/mammal/bladder/bladder1 - "Mammal, bladder (LM, Medium)"
- Virtual Slidebox at Univ. Iowa Slide 445
- Anatomy photo:43:07-0100 at the SUNY Downstate Medical Center - "The Female Pelvis: The Urinary bladder"
- Anatomy photo:44:04-0103 at the SUNY Downstate Medical Center - "The Male Pelvis: The Urinary bladder"
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Human systems and organs
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TA 2–4:
MS |
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Skeletal system
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- Bone
- Carpus
- Collar bone (clavicle)
- Thigh bone (femur)
- Fibula
- Humerus
- Mandible
- Metacarpus
- Metatarsus
- Ossicles
- Patella
- Phalanges
- Radius
- Skull (cranium)
- Tarsus
- Tibia
- Ulna
- Rib
- Vertebra
- Pelvis
- Sternum
- Cartilage
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Joints
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- Fibrous joint
- Cartilaginous joint
- Synovial joint
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Muscular system
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TA 5–11:
splanchnic/
viscus |
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mostly
Thoracic
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mostly
Abdominopelvic
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Digestive system+
adnexa
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- Mouth
- upper GI
- Oropharynx
- Laryngopharynx
- Esophagus
- Stomach
- lower GI
- Small intestine
- Appendix
- Colon
- Rectum
- Anus
- accessory
- Liver
- Biliary tract
- Pancreas
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GU: Urinary system
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- Kidney
- Ureter
- Bladder
- Urethra
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GU: Reproductive system
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- Female
- Uterus
- Vagina
- Vulva
- Ovary
- Placenta
- Male
- Scrotum
- Penis
- Prostate
- Testicle
- Seminal vesicle
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Endocrine system
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- Pituitary
- Pineal
- Thyroid
- Parathyroid
- Adrenal
- Islets of Langerhans
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| TA 12–16 |
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Circulatory system
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Cardiovascular system
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- peripheral
- Artery
- Vein
- Lymphatic vessel
- Heart
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Lymphatic system
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- primary
- secondary
- CNS equivalent
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Nervous system
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Integumentary system
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- Skin
- Subcutaneous tissue
- Breast
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Blood
(Non-TA) |
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General anatomy: systems and organs, regional anatomy, planes and lines, superficial axial anatomy, superficial anatomy of limbs
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Anatomy: urinary system (TA A08, TH H3.06, GA 11.1215)
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| Abdomen |
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Kidneys
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Layers
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- Renal fascia
- Renal capsule
- Renal cortex
- Renal medulla
- Renal sinus
- Renal pyramids
- medullary interstitium
- Renal lobe
- Cortical lobule
- Medullary ray
- Nephron
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Intrarenal arteries
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- Renal artery
- Segmental arteries
- Interlobar arteries
- Arcuate arteries
- Interlobular arteries
- Afferent arterioles
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Renal tubule
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- Renal corpuscle
- Glomerulus
- Bowman's capsule
- Proximal tubule
- Loop of Henle
- Descending
- Thin ascending
- Thick ascending
- Distal convoluted tubule
- Connecting tubule
- Collecting ducts aka Duct of Belini
- Renal papilla
- Minor calyx
- Major calyx
- Renal pelvis
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Intrarenal veins
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- Efferent arterioles
- Peritubular capillaries/Vasa recta
- Arcuate vein
- Interlobar veins
- Renal vein
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JGA
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- Macula densa
- Juxtaglomerular cells
- Mesangium/Extraglomerular mesangial cell
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Filtration
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- Glomerular basement membrane
- Podocyte
- Filtration slits
- Mesangium/Intraglomerular mesangial cell
- Tubular fluid
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Ureters
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- Orifice of ureter
- Adventitia
- Muscular layer
- Mucosa
- Ureteropelvic junction
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| Pelvis |
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Bladder
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- Apex
- Uvula
- Neck
- Median umbilical ligament
- Muscular layer
- Mucosa
- Submucosa
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Urethra
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- Urethral sphincters
- External sphincter muscle of male urethra
- External sphincter muscle of female urethra
- Internal sphincter muscle of urethra
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noco/acba/cong/tumr, sysi/epon, urte
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proc/itvp, drug (G4B), blte, urte
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